Further understanding is sought of the fundamental metabolic behavior of the major classes of plasma lipoproteins implicated in the pathogenesis of several of the common killing cardiovascular diseases of man. Effort will be concentrated upon scrutiny of the characteristics and metabolic behavior of the high density class of lipoproteins. In order to obtain data as transferable to man as possible, the experimental manipulations will be accomplished in baboons under carefully controlled laboratory conditions. Present and additional schemes for the resolution of multiple peptide components will be further evaluated by characterizing the isolated peptides by disc gel electrophoresis and amino acid and carbohydrate composition. Observations of production, turnover, and exchange rates of the various HDL peptides and metabolically related peptides in other lipoprotein classes will be conducted in intact subjects and in isolated perfused liver preparations. Thus a clearer understanding of the hepatic responsibilities in specific aspects of lipoprotein metabolism will be sought. Biosynthetic labeling with radioisotopic amino acid precursors will be employed.